The present invention relates to an apparatus for controlling ignition timing for an engine, and more particularly to a unit structure for allowing principal components of such an apparatus to be shared by a variety of engines having different numbers of cylinders and reference position sensors.
Recent rapid developments in electronics technology have resulted in an increased tendency for engine ignition timing to be controlled by a digital system. For example, an electronic engine ignition control circuit for two-wheeled motorcycles is supplied with crank angle pulses generated each time the crank shaft rotates through a unit angle and with reference position pulses indicative of reference positions of the crank shaft. The control circuit counts and processes the crank angle pulses with the reference position pulses being used as references for determining a dwell angle and for controlling ignition timing.
There are many kinds of engines available which have different numbers of cylinders and reference position sensors. It has been customary to provide as many different engine ignition control devices as there are varying kinds of engines. Therefore, fabricating and keeping such engine ignition control apparatus has been quite time-consuming and tedious.